Carbon dioxide removal processes by alkanolamines in aqueous organic solvents

PhD ceremony: Mr. E.S. Hamborg, 13.15 uur, Academiegebouw, Broerstraat 5, Groningen

Title: Carbon dioxide removal processes by alkanolamines in aqueous organic solvents

Promotor(s): prof. G.F. Versteeg

Faculty: Mathematics and Natural Sciences

 

Acid gas removal by absorption has been used to separate carbon dioxide (CO2) and other acid gases from natural gas, hydrogen, and other gas streams since the 1930s. With increased awareness of the consequences of CO2 emissions to the atmosphere, the focus of removing CO2 from low pressure gas streams has gained increased attention the last years. In particular, this applies to the removal of CO2 from the flue gases of fossil-fueled power plants.

In the current work, efforts have been made to develop and understand the fundamentals of; (1) a CO2 removal process based on alkanolamines in aqueous organic solvents, and (2) gas-liquid desorption processes. Dissociation constants of several amines, alkanolamines, and amino acids have been experimentally determined in aqueous and aqueous organic solvents. The reported results and standard state thermodynamic properties provide information about the use of these compounds and solutions as possible absorbents for acid gas removal. Liquid phase mass transfer coefficients, chemical enhancement factors, and kinetic rate parameters for absorption and desorption processes have been experimentally determined over a wide range of operating conditions. These parameters have been related to each other at identical operating conditions, and by such provide information about gas-liquid desorption processes.

The aforementioned results have been implemented in the Procede Process Simulator, which was used in order to simulate a CO2 removal process based on alkanolamines in aqueous organic solvents. The simulation results showed a decreased desorber reboiler duty and temperatures compared to processes based on alkanolamines in purely aqueous solvents.